fix(openclaw-bridge): implement correct v3 device auth protocol

- device.id = SHA256(rawPubKey, hex) — not a random UUID
- device.publicKey = raw 32-byte key encoded as base64url (not SPKI DER)
- sign the full v3 payload string (not just raw nonce bytes):
  "v3|{deviceId}|{clientId}|{mode}|{role}|{scopes}|{ts}|{token}|{nonce}|{platform}|"
- device.signature encoded as base64url

Matches buildDeviceAuthPayloadV3/verifyDeviceSignature from openclaw dist.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/openclaw-bridge/src/openclaw-client.ts

@@ -6,11 +6,19 @@
  *   Response: { type:"res", id, ok:boolean, payload?, error? }
  *   Event:    { type:"event", event, payload?, seq? }
  *
- * Authentication:
+ * Authentication (v3 device-signature protocol):
  *   1. Server sends "connect.challenge" event with { nonce, timestamp }
- *   2. Client signs the nonce with an ephemeral Ed25519 key
- *   3. Client sends "connect" req with auth.token + device.{id,publicKey,signature,signedAt}
- *   4. Server responds with ok:true → connection is ready
+ *   2. Client builds payload:
+ *      "v3|{deviceId}|{clientId}|{clientMode}|{role}|{scopes}|{signedAtMs}|{token}|{nonce}|{platform}|"
+ *   3. Client signs payload (UTF-8) with ephemeral Ed25519 key
+ *   4. Client sends "connect" req with:
+ *      - client.id = "gateway-client", client.mode = "backend", client.platform = "node"
+ *      - auth.token = OPENCLAW_GATEWAY_TOKEN
+ *      - device.id = SHA256(rawPubKey, hex), device.nonce = nonce
+ *      - device.publicKey = rawPubKey (base64url, 32 bytes)
+ *      - device.signature = base64url(signed payload)
+ *      - device.signedAt = Date.now()
+ *   5. Server responds with ok:true → connection is ready
  */
 
 import WebSocket from 'ws';
@@ -43,6 +51,21 @@ interface EventFrame {
 
 type Frame = ReqFrame | ResFrame | EventFrame;
 
+// ── Helpers (mirror openclaw/openclaw internals) ──────────────────────────────
+
+function base64UrlEncode(buf: Buffer): string {
+  return buf.toString('base64').replaceAll('+', '-').replaceAll('/', '_').replace(/=+$/g, '');
+}
+
+// Ed25519 SPKI prefix (ASN.1 DER) — 12 bytes
+const ED25519_SPKI_PREFIX = Buffer.from('302a300506032b6570032100', 'hex');
+
+function getRawPublicKey(keyObject: crypto.KeyObject): Buffer {
+  const spki = keyObject.export({ type: 'spki', format: 'der' }) as Buffer;
+  // Raw key is the 32 bytes after the 12-byte SPKI prefix
+  return spki.subarray(ED25519_SPKI_PREFIX.length);
+}
+
 // ── Client ────────────────────────────────────────────────────────────────────
 
 export class OpenClawClient {
@@ -55,13 +78,20 @@ export class OpenClawClient {
   private msgCounter = 0;
 
   // Ephemeral Ed25519 key pair — generated once per client instance
-  private readonly deviceId = crypto.randomUUID();
   private readonly keyPair = crypto.generateKeyPairSync('ed25519');
+  // Raw 32-byte public key (base64url) — used as device.publicKey
+  private readonly rawPubKeyB64Url: string;
+  // device.id = SHA256(rawPubKey, hex) — required by openclaw gateway
+  private readonly deviceId: string;
 
   constructor(
     private readonly gatewayUrl: string,
     private readonly token: string,
-  ) {}
+  ) {
+    const rawPub = getRawPublicKey(this.keyPair.publicKey);
+    this.rawPubKeyB64Url = base64UrlEncode(rawPub);
+    this.deviceId = crypto.createHash('sha256').update(rawPub).digest('hex');
+  }
 
   connect(): Promise<void> {
     return new Promise((resolve, reject) => {
@@ -141,10 +171,31 @@ export class OpenClawClient {
   }
 
   private async sendHandshake(nonce: string): Promise<void> {
-    // Sign the nonce (hex string → Buffer) with our ephemeral private key
-    const nonceBuffer = Buffer.from(nonce, 'hex');
-    const signature = crypto.sign(null, nonceBuffer, this.keyPair.privateKey);
-    const pubKeyDer = this.keyPair.publicKey.export({ type: 'spki', format: 'der' });
+    const signedAt = Date.now();
+    const scopes = ['operator.read', 'operator.write'];
+    const clientId = 'gateway-client';
+    const clientMode = 'backend';
+    const role = 'operator';
+    const platform = 'node';
+
+    // V3 payload (matches buildDeviceAuthPayloadV3 in openclaw source):
+    // "v3|{deviceId}|{clientId}|{clientMode}|{role}|{scopes}|{signedAtMs}|{token}|{nonce}|{platform}|{deviceFamily}"
+    const payload = [
+      'v3',
+      this.deviceId,
+      clientId,
+      clientMode,
+      role,
+      scopes.join(','),
+      String(signedAt),
+      this.token,
+      nonce,
+      platform,
+      '',  // deviceFamily (empty)
+    ].join('|');
+
+    // Sign as UTF-8 string (not raw hex bytes)
+    const sig = crypto.sign(null, Buffer.from(payload, 'utf8'), this.keyPair.privateKey);
 
     const req: ReqFrame = {
       type: 'req',
@@ -154,20 +205,20 @@ export class OpenClawClient {
         minProtocol: 3,
         maxProtocol: 3,
         client: {
-          id: 'gateway-client',
+          id: clientId,
           version: '1.0.0',
-          platform: 'node',
-          mode: 'backend',
+          platform,
+          mode: clientMode,
         },
-        role: 'operator',
-        scopes: ['operator.read', 'operator.write'],
+        role,
+        scopes,
         auth: { token: this.token },
         device: {
           id: this.deviceId,
-          nonce: nonce,
-          publicKey: pubKeyDer.toString('base64'),
-          signature: signature.toString('base64'),
-          signedAt: Date.now(),
+          nonce,
+          publicKey: this.rawPubKeyB64Url,
+          signature: base64UrlEncode(sig),
+          signedAt,
         },
       },
     };